Look, it cannot be seen,
So it is called invisible.
Listen, it cannot be heard,
So it is called soundless.
Touch, it cannot be caught,
So it is called elusive.
These three cannot be examined,
So they unite into one.
Above it there is no light,
Below it there is no darkness.
Endlessness beyond description.
It returns to non-existence.
It is called the shapeless shape,
The substance without form.
It is called obscurely evasive.
Meet it and you do not see its beginning,
Follow it and you do not see its end.
Hold on to the ancient Way to master the present,
And to learn the distant beginning.
This is called the unbroken strand of the Way.
Tao Te Ching Chapter 14 by Lao Tzu